


Three is a charm, Two is not the same

by IamMidnight



Series: Midnight's House of Sin [1]
Category: Voltron: Legendary Defender
Genre: ABO, Alpha Keith (Voltron), Alpha Prime, Alpha Shiro (Voltron), Alpha/Alpha, Alpha/Beta/Omega Dynamics, Alpha/Omega, Bonding, But obviously ABO and They Are Dating, Canon Divergence maybe?, Canon Universe, Dark Shiro (Voltron), Dubious Consent, Dubious consent for multiple characters, Galra Keith (Voltron), Keith Galras Out, Knotting, M/M, Mating, Mind Break, Multi, Omega Lance (Voltron), Omega Verse, Pheromones
Language: English
Status: Completed
Published: 2018-10-06
Updated: 2018-10-06
Packaged: 2019-07-27 08:11:33
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 4,164
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16215011
Author URL: https://archiveofourown.org/users/IamMidnight/pseuds/IamMidnight
Summary: A relationship between two alphas is always tricky.So, Shiro has to take some drastic steps to keep Keith in his life.





	Three is a charm, Two is not the same

**Author's Note:**

> Let me know if you have any questions about the tags or possible triggers.

A relationship between two alphas is always tricky.

Quite frankly, it is just a lot of testosterone in the same place. Tempers, aggression, natural instincts…they tend to clash when two alphas try to be something other than friends or comrades.

This is especially true when you are an alpha prime, like Shiro. Or, at least that is what people say.

They are wrong.

Shiro loves Keith and Keith loves him. It works for them and that is all that matters.

Part of the reason his relationship with Keith works is because he is so dominant as an alpha prime. Keith accepts Shiro as his leader, as the head alpha. They form a shockingly close relationship, to the surprise of all around them.

Of course, it helps that Keith is so young, inexperienced, and small for his age. Shiro isn’t afraid to admit that, if he had caught Keith at a different time, an older, more established alpha Keith, that this may not have worked.

As morbid as it sounds, it also helps that Keith is an orphan. His past leads him to crave companionship, seek it out even with an alpha prime. He looks up to Shiro. Thinks of him as a father figure or maybe an older brother. Not in a weird way of course. It just makes the occasional argument between them easier to handle because Keith defers to him, understands that Shiro is older, wiser, and stronger.  

He also craves a firm hand, something he didn’t get much of as a child. Shiro can provide that. Stability. A firm hand. Discipline.

It works. Whatever careful balance they are able to strike works.

Keith is hopelessly devoted to him and Shiro knows it. Shiro loves his little alpha. Loves his fire. Loves how he only submits for him, for Shiro. Loves that he gets to see sides of Keith that no one else gets to see.

Loves that another alpha has submitted to him so thoroughly.

Keith is intoxicating for Shiro and he will never let him go. Ever.

~*~*~*~*~*~*~*~*~

Then Kerberos happens.

One Galra captivity later, some issues with clones, and an ongoing space war cause a lot of changes for their relationship. At first, they are hesitant to restart the relationship after being reunited. There are bigger issues at hand, new complications. But, he knows Keith is still devoted to him. And he is still devoted to Keith. So, eventually they fall back together, as Shiro knows they are destined to do as many times as it takes.  

It is around this time that Keith finally grows up too. Becomes the alpha he was always meant to be. He is inches taller, broader, more muscular, and with a few new scars. Shiro loves the way he looks.

However…

It causes issues, right from the start.  

Not that they are any less in love. Keith still tenderly loves him and is more devoted than ever. In some ways, they are stronger than ever.

In other ways, they are struggling.

Keith is flooded with new instincts, new hormones, telling him to breed, dominate, knot.

They argue more than ever, stupid fights, far stupider than any fights they had before going to space. Shiro understands though. He gets it.

Keith is coming into his own. He is likely an alpha prime himself. And, Galra, full of aggression and animal instincts. Keith’s heart belongs to Shiro, but his body is increasingly telling him to fight against submitting to another alpha, to find a willing, wet body to fuck senseless.

Which would never be Shiro. He would never let Keith penetrate him. He had sucked him off before, used his hands, made Keith hump his leg, but he is an alpha prime. He isn’t ever letting anyone inside him.

He realizes that things need to change one day while buried balls deep inside of Keith. Keith had always enjoyed letting Shiro take him, letting Shiro knot him despite being an alpha himself.

They had been having sex less frequently though and, right now, Shiro can sense that Keith is resentful. Angry. That he is losing the battle against his hormones that tell him to fight against being spread out underneath another alpha.

Things need to change, Shiro realizes. Or he will lose Keith.

He will lose the love of his life.

And Shiro will do anything to avoid that happening.

~*~*~*~*~*~*~*~*~

The solution to all their problems basically falls in Shiro’s lap one day. It is an option he hadn’t really considered until this moment while sparring with the other paladins.

Lance and Pidge are messing around with each other while Keith watches. As Shiro walks closer, he smells Keith’s undeniable arousal. His desire. A smidge of pining. He follows Keith’s gaze to Lance and then back to Keith.

Keith never realizes that he isn’t subtle at all. He awkwardly pretends like he is cleaning one of the practice weapons that doesn’t even need to be cleaned because the castle does it for them. He brings up the weather, of all things. Shiro chuckles. This is the man he loves.

He leans over Keith’s shoulder, bringing his mouth close to Keith’s ear.

“I know you want him.”

Keith freezes. “What? No, I have no idea…that’s insane…I would never…”

“Keith, I know,” Shiro drops his voice even lower, wrapping possessive arms around Keith’s hips.

Keith is silent for a moment. “I can’t help it Shiro. I’m sorry. I would never act on it, ever.”

“So, Lance, huh?”

Shiro swirls little circles with his thumb across Keith’s hips and stares at the tall boy trying to flip Pidge over his head.

~*~*~*~*~*~*~*~*~

Shiro had never thought of Lance that way.

He knows Lance is about the same age as Keith and even older than when he and Keith first started dating, but something just feels young about Lance. Innocent in a way Keith never was.  

I mean, don’t misunderstand. Shiro knows that Lance is an attractive boy. He knows he is highly desirable especially as a male omega. He is a talented paladin, a great shot, a great right hand man.

But a romantic partner?

It isn’t unheard of. Especially in older times when omegas were still pets, it was very common to see two alphas sharing an omega. Of course, pets don’t really exist anymore (unless by choice) but polyamory exists. Why not two alphas and an omega?

It makes perfect sense in a lot of ways. An omega can soothe tensions, reduce aggression. Act as the salve on any festering hormonal rage inside of alphas. It also solves the problem of Keith needing somewhere to knot, to fulfill those instincts that he can’t with Shiro.

So maybe he didn’t think of Lance that way before, but he tries over the next week to see him that way. To see him how Keith does.

Focuses on his slender waist. His surprising gracefulness at times. How adorable he is when he laughs or blushes.

He gets it. It helps that Keith is really into him. He tries to hide it, but Shiro knows. He can sense it, he can smell it. He is shocked that other people don’t realize it.

He brings it up to Keith one late night after fucking him. Keith had been extra pliant lately, extra obedient. He knows the black-haired boy feels bad now that Shiro knows about his little crush. He knows that Shiro has picked up on his extra aggression lately too.

“Why don’t we consider opening up the relationship?”

Keith stiffens, eyes flying open in horror.

“Shiro.” His voice is choked already.

“Calm down, Keith.”

“Are you breaking up with me?”

“No, I just think…”

“You promised you would never leave me!”

“Keith, calm down.”

“I’ll try harder. I can control this. You know…Pidge was telling me that there are some experimental drugs that they are trialing on Earth anyway that can…”

Shiro wraps a hand around Keith’s neck.

“Keith. Stop.”

He does, closing his mouth and looking at Shiro expectantly.

“You will not take any drugs to suppress who you are. You are my alpha and my galra. Understand?”

Keith nods.

“I only meant that I will do whatever it takes to keep this relationship healthy and I think an omega would do the trick. And I know you like Lance. I could like Lance too.”

Keith snorts. “What makes you think he would be interested in us anyway? He has been chasing Allura for years and even when he wasn’t he didn’t act interested in me or you.”

“Allura doesn’t want him. She never will. And I think he is attracted to both of us.”

Keith shakes his head.

“He blushes around you sometimes. Watches you when he doesn’t think anyone is looking. He does the same thing to me. It is only natural. He is an omega around two alpha primes. It is practically coded in his DNA to want us.”

“He does? He watches me?”

“Oh yes.”

“But Lance is like, the least omega omega ever. It isn’t like he is submissive to us.”

“Are you sure about that? Who gives the orders and who follows them? Who did the Black Lion choose to lead the most powerful weapon in the world and who was chosen to be our support?”

Keith mulls it over.

“There is a part of Lance that is very traditionally omega,” Shiro continues. “He wants someone to give him orders. He wants to belong to someone. He likes being spoiled. But, he isn’t a textbook omega, of course. But, really, would a textbook omega even work for two alpha primes like us?”

“No. No, a regular omega wouldn’t do at all.”

“We would tear someone completely passive and submissive apart. We need an omega with a little bite to his bark. Someone who can challenge us.”

Keith nods, eyes lighting up. “Lance is perfect.”

“He is.”

“But how do we convince him of that?”

“We should let nature take its course.”

“But Lance…”

“We will help him through his next heat. Trust me, after that week he will be ours.”

“He doesn’t even have heats. He is on the pill.”

“I mean, there is only so long you can put off having a heat.”

“When should we talk to him about it?”

“We are not going to talk to him.”

“That doesn’t sound right…”

“Lance is one of those people who would overthink it. He thinks too much sometimes and you aren’t good at talking about these things. It would overcomplicate things.”

“That doesn’t sound completely consensual.”

“On the contrary, if we just talk to him about this he may feel pressured to say yes with two of the leaders of Voltron expecting it of him.”

Keith shakes his head vehemently. “Lance needs to want it too.”

“That is why my plan is the best one. We will enter Lance’s nest when he is in heat.”

Keith still looks unsure.

“We are at our most honest when we are in heat or rut. If he doesn’t want us, trust me, we will know. Omegas will go feral if an alpha they don’t accept tries to mate with them. A feral omega would be able to take down both of us, easily.”

“Really?” Keith sits up.

“Yes. If Lance is opposed, he will reject us and we will leave and think about other solutions. It will be his choice, entirely.”

Keith fiddles with the edge of the sheets.  

“And this won’t mess up our relationship?”

It is times like these that Shiro remembers just how young Keith is.

“No. It will only make us stronger.”

“Ok,” Keith nods.

Keith always trusts him.

~*~*~*~*~*~*~*~*~

It isn’t a complete lie.

Ok, maybe it is. Keith is so inexperienced and never had anyone to tell him how everything works. So, the lie about the feral omega is one that he buys.

In reality, Shiro knows that Lance would be overwhelmed by having two alpha primes near him. He would submit whether he wanted them or not. Then, once they had both bitten him, any apprehensions he might have had will be eliminated by the venom in his veins.

Shiro’s concern is that, rather than rejecting them, that the experience and sudden bonding would change him too much, would alter him so much that he would be unable to be a paladin anymore, unable to do anything but curl at their feet and take their cocks when they felt like it.

He was banking on Lance being strong enough to survive with most of his personality intact, most of his awareness.

There is a good chance they could break him though and, boy, Shiro does not want to have to explain that one to Allura, Pidge, and Hunk. Not to mention Lance’s family.

Or even Keith, who he hadn’t dared to mention the possibility of breaking Lance.  

It is worth the risk to save what he has with Keith though.

~*~*~*~*~*~*~*~*~

Everything really falls into place easier than Shiro could have hoped. He just waits until Lance is low on his suppressants and then suddenly finds some distress signals far away from anywhere that could provide more for him.

Lance doesn’t seem too worried. It just means he will have to go through his heat. He informs Shiro and Allura matter-of-factly and then gathers some extra bedding and finds an extra room on another floor. He even tells them where the room is, completely ignorant of what Shiro has planned for him.

So trusting.

They can both smell his pre-heat. Shiro can handle it. He isn’t the type to go crazy over an omega’s heat.

But Keith is jittery, even showing signs of his rut. Shiro hadn’t realized just how far gone Keith is for Lance. The beginnings of Keith’s rut starts to trigger Shiro and this is not ideal. It is already going to be a lot for Lance to handle. This is without having both of them in rut.

He considers calling it off, but Keith’s desire changes his mind. He isn’t sure he could go back on his offer, not when Keith wants it this much.

It is a testament to how devoted Keith is to Shiro that he isn’t trying to fight Shiro though. Normally, two alphas would fight over an omega. Keith though seems extra tender with him. The sweet side of Keith emerges. The side that can be nurturing. He keeps asking Shiro questions about how they can make Lance more comfortable, what they can bring the omega to make him happy.

Shiro starts to worry that Lance will reject them, by some freak of nature, that their alpha pheromones won’t be enough, and that he will crush Keith. Just crush him. Keith is already so stupidly devoted to Lance.

So, when the special day comes, Shiro tells Keith to go grab more food and water and bring it to Lance’s room where he will meet him before going in. It is something they will need, but he has another motivation too. Keith scampers off and Shiro immediately heads for Lance’s room. He swings open the door and is struck by a sugary sweet scent. Shiro wrinkles his nose slightly.  

Lance sits up abruptly in his bed.

“Shiro?” he asks, eyes already hazy and dark.

He walks briskly over, ignoring Lance’s stuttered “What’s going on.”

He pulls Lance close and commands him, with as much force as he can muster, directly in his ear.

“You want to mate with me and Keith. Let it happen. Be a good boy.”

Lance goes limp, looking up at Shiro with wide eyes.

“Alpha?” he asks and Shiro smiles.  

Lance really is a good boy.

A good omega who is eager to submit to an alpha prime. Eager to please his leader. Completely willing to follow an alpha command without question.

Then Keith is there, confused why Shiro went in first, but immediately panting at Lance’s smell.

“Come here, Keith,” Shiro beckons to him.

Keith walks over, jaw tense, apprehension and hope in his eyes. “Lance? Do you want this? Do you really accept us?”

Shiro digs his fingers into Lance’s back. It is unnecessary. Lance is completely under right now, completely in omega headspace. He probably didn’t even need to command him.

“I want to mate with you. I want to be a good boy,” Lance responds, looking up at Keith with heavily lidded eyes.

Keith gasps and awkwardly hugs both Shiro and Lance. He is so happy that Shiro allows the awkward hug even as Lance’s arousal grows, wet spot growing on the bed.

Normally, Shiro would go first. It is his right as the head alpha. But, Lance is really a gift for Keith and Keith looks like he is about to jump out of his skin. He gestures at Keith to go for it.

Keith can barely control himself though, ripping Lance’s underwear off with his bare hands, leaving them in tatters on the floor.

Lance whimpers and he is scared, even with the command and alpha pheromones drowning him. Shiro can basically taste his fear. He knows Lance is a virgin and, well, at this moment Keith is a little scary even to Shiro. The Galra is lurking, flashes of gentle purple and yellow eyes emerging.

He is fully into his rut and losing control with an omega in front of him. Shiro understands. Keith has probably never experienced an omega in heat before. In some ways, he is still a virgin himself and, once given consent by Lance, seems to be unable to control the instincts telling him to fuck the willing body in front of him.  

Lance goes to cover himself, scooting away from Keith, trembling.

 _Well, we can’t have that_ , Shiro thinks. He gets behind Lance on the bed and grabs his wrists, pulling the omega back down onto the bed and pinning his hands above his head. Keith is on him a second later, spreading his legs, practically drooling.

“Let him take you,” Shiro commands quietly, directly into Lance’s ear. He pumps out as much arousing pheromones as he can. Lance’s eyes immediately go hazy and his legs fall open. Keith is mounting him a second later. A string of adorable little groans leave Keith’s mouth as he experiences his first omega. His eyes are practically rolling in the back of his head as he pushes deep inside of Lance, as deep as he can push himself.

Lance squirms and Shiro tightens his grip on his wrists, pinning him down and keeping his shoulders back on the bed even as his back arches. Shiro croons in his ear, a bit sympathetic that Keith didn’t even bother prepping him.  

Then Keith is fucking him, for real. Short, hard, fast thrusts, much like a dog.

Keith makes some of the most beautiful noises Shiro has ever heard while mating Lance.

It isn’t long before Lance is rising his hips to meet Keith’s thrusts. _It is only natural_ , Shiro thinks. What a treat for Lance to get bred by an alpha prime like Keith. His body is eager to take it. Keith grips at Lance’s thighs, spreading his legs wider and using them to pull Lance into his cock with every thrust.

It is savage, a brutal pace, and both boys are crying out, grunting, moaning at the sensations.

Shiro keeps Lance firmly pinned to the bed, offering him up to Keith. This is how much he loves Keith. This is what he is willing to do for him.

It isn’t long before Keith opens his eyes and they are slitted and yellow. A dash of purple crosses his face and claws dig into Lance’s thighs. His moans start to sound more like growls.  

He is going full Galra on top of Lance and Shiro briefly wonders if he might accidentally hurt Lance, but quickly decides that he won’t. Alphas don’t usually hurt omegas.

Shiro can smell the moment Keith knots him, no longer able to pull out at all, collapsing on top of Lance with a strangled moan. Shiro quickly grabs Lance’s chin, twisting his head so that his scent gland is exposed.

“Keith, do it, now. Bite him.”

And he does. Sinks those fangs directly into Lance’s scent gland.

Lance immediately goes completely limp.

Shiro can relax now.

He gets off the bed and sits down on a nearby chair, grabbing a water bottle while he is at it.

He passively stares at the sight before him. Keith is on top of Lance, pale body nearly covering up Lance’s tan one. Keith and Lance are in their own world right now. Keith remains latched onto his neck, biting down, scarring Lance, marking him. His hands stroke Lance’s head, petting him. He occasionally grinds his hips and fills Lance even more.  

It makes for quite the sight.

When he finally rolls off, he is back to being Keith. The Galra is gone for now and he cradles Lance close to him. He sprinkles kisses up and down the boy’s face, murmuring sweet, gentle words to the exhausted omega.

There really isn’t time for cuddles though because now it is Shiro’s turn.

He carefully pulls Lance out of Keith’s arms. Keith nods even though he clearly doesn’t want to let go of Lance. Shiro positions the omega on his hands and knees. Lance is so exhausted after the experience with Keith that he immediately collapses, unable to hold his body weight up. Shiro shrugs and pulls his hips up himself, letting Lance lay face down on the bed. Shiro takes a deep breath and then quickly pushes in, smiling as Lance whines.

He is big. Bigger than Keith. Big enough that he is probably stretching Lance in ways that Keith couldn’t. There is just a bit of resistance when he pushes the last inch in. He gives Lance a moment to adjust, looking down at the sweaty boy. It feels good inside Lance, it does. Shiro knows this is what his body should crave-a sweet, obedient omega, slick and wet and warm.

But, Shiro has always preferred other alphas. He would rather be inside Keith right now, but this is necessary to seal the deal, so to say.  

He finally starts moving, drawing little grunts and whimpers from the boy beneath him. He sets a much slower pace than Keith did. He slowly rocks in and out of Lance, pulling almost all the way out before sliding back in and grinding just a bit once fully seated.

He isn’t quite able to reach that point he needs to reach until Keith crawls over, laying down next to Lance and stroking his fingers through his hair. Shiro closes his eyes and imagines he is inside of Keith instead of Lance and finally feels the heat of his orgasm approaching. A moment later, he has finally knotted the omega underneath him.

He leans down, covering the much smaller body beneath him, and bites savagely into the other side of his scent gland. Lance is still and unmoving. Shiro smiles down at the two bite marks on Lance’s neck. Him and Keith. Together in everything they do.

He doesn’t remain knotted to him for long. He pats Lance on the back and rolls over once he can.

Lance collapses onto the bed, already closing his eyes. Being bred and bonded twice in an hour will do that to you. Shiro pulls Keith beside him. Lance wouldn’t wake up for a few more hours, ready for the next round. Might as well rest up for the next few days. He curls up with Keith and closes his eyes, not even bothering to wipe off or put clothes on. At some point, he will fuck Keith in front of Lance, making sure everyone knew who the head of this dynamic is. But, for now, he just wants to enjoy holding Keith close to him and smelling his happiness.

~*~*~*~*~*~*~*~*~

 

He wakes up with empty arms.

Keith is sitting next to Lance, wiping a towel down his body. When Shiro sits up, Keith looks at him, brow furrowed in concern.

“He seems really out of it. I got him to drink a little bit, but he won’t eat and he seems…like he is drunk or something. Or sedated. I don’t know. Is this normal?”

Shiro cringes looking at the glassy eyed omega who is timidly looking up at Keith.  

He hides his apprehension though. “Of course it is normal. He is in his heat and surrounded by a lot of alpha right now. He is also newly bonded. He will be Lance again soon.”

 _Hopefully,_ Shiro thinks. He mentally crosses his fingers.

Keith seems satisfied though. He curls up again between Lance and Shiro. He gently cradles the other boy, kissing his forehead and telling him he loves him.

Then he turns over, smiling widely at Shiro.

“I love you too. Forever.”

Shiro pulls Keith into a kiss.

He loves Keith too.

Forever.

Whatever it takes.

 

   

**Author's Note:**

> I am hoping to complete this Kinktober/Darktober challenge, but I am going to be honest it will either not be 31 days or I will be finishing Kinktober in like, December.  
> I am taking suggestions-I don't only do ABO and I will also do any pairing in Voltron. They can also just be darkfics and not straight up kink or sexy times. 
> 
> Here are the current prompts I am working on or trying to complete. 
> 
> -(Finished) ABO Omega Lance with Alpha Keith and Shiro doing bad things to him  
> -(Half-Written) Non-con somnophilia (Can't decide if I want this to just be Lance or James and Lance. Keith would be the unlucky one in this fic)  
> -(Half-written) Breathplay gone wrong (Lance and Shiro)  
> -(Outlined) Dark mermaid/human non-con fic (Lance as mermaid)  
> -(Outlined) Pleasure slave/Forced Empress Lotura short  
> -(Outlined, need an ending) Lance cutting himself with Keith's knife  
> -Lotor noncon (Lance as victim) (I feel like this has been done a LOT so I would need to think of an "angle" into it or a way to make it unique/my own? Someone suggested Lotor as the victim and now that might be interesting...)


End file.
